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A comparative study was carried out aiming at characterizing the thermal conductivity of rocks sampled in a borehole heat exchanger field. Twenty-three samples were analysed with four different methods based on both steady-state and transient approaches: transient divided bar (TDB), transient line source (TLS), optical scanning (OS), and guarded hot plate (GHP). Moreover, mineral composition (from XRD analyses), P-wave velocity, and density were investigated to assess the petro-physical heterogeneity and to investigate possible causes of divergence between the methods. The results of thermal conductivity showed that TLS systematically underestimates thermal conductivity on rock samples by 10–30% compared to the other devices. The differences between TDB and OS, and GHP and OS are smaller (about 6% and 10%, respectively). The average deviation between TDB and GHP, for which the specimen preparation and the measurement procedure were similar, is about 10%. In general, the differences are ascribable to sample preparation, heterogeneity and anisotropy of the rocks, and contact thermal resistance, rather than the intrinsic accuracy of the device. In case of good-quality and homogeneous samples, uncertainty can be as low as 5%, but, due to the above-mentioned factors, usually uncertainty is as large as 10%. Opposite relationships between thermal conductivity and P-wave velocity were observed when analysing parallel and perpendicular to the main rock foliation. Perpendicular conductivity values grow with increasing perpendicular sonic velocity, while parallel values exhibit an inverse trend. Thermal conductivity also appears to be inversely correlated to density. In quartz-rich samples, high thermal conductivity and low density were observed. In samples with calcite or other likely dense mineral phases, we noticed that lower thermal conductivity corresponds to higher density. The presence of micas is likely to mask major differences between silicate and carbonate samples.

The iron-oxide-copper-gold (IOCG) skarns of the Tatatila-Las Minas mining district in central Mexico represent a structurally-controlled, exhumed fossil geothermal system located in the eastern sector of the Trans-Mexican Volcanic Belt (TMVB). The district was historically exploited for gold and copper mineralization. The emplacement of the ore bodies was controlled by regional Neogene–Quaternary NE- and NW-striking fault systems formed during the extensional evolution of the TMVB. These faults acted as conduits for high-temperature hydrothermal fluids circulating during the cooling of the Neogene magmatic intrusions. By integrating detailed field study with available exploration borehole data, the spatial distribution of the skarn bodies was reconstructed. Three main emplacement geometries were identified: (a) at contacts between magmatic bodies and host rocks, (b) as lenticular or irregular bodies parallel to the host rock foliation, and (c) at the intersections of near-orthogonal faults. Although structural controls on skarn formation represent a key factor in ore emplacement, their analysis remains scarcely explored. This paper therefore contributes to filling this gap by providing a detailed characterization of the structural framework governing IOCG skarn development at Tatatila–Las Minas. The results improve understanding of IOCG systems formation and provide predictive criteria for mineral exploration in similar geological settings, potentially reducing exploration and mining risks.

The iron-oxide-copper-gold (IOCG) skarns of the Tatatila-Las Minas mining district in central Mexico represent a structurally-controlled, exhumed fossil geothermal system located in the eastern sector of the Trans-Mexican Volcanic Belt (TMVB). The district was historically exploited for gold and copper mineralization. The emplacement of the ore bodies was controlled by regional Neogene–Quaternary NE- and NW-striking fault systems formed during the extensional evolution of the TMVB. These faults acted as conduits for high-temperature hydrothermal fluids circulating during the cooling of the Neogene magmatic intrusions. By integrating detailed field study with available exploration borehole data, the spatial distribution of the skarn bodies was reconstructed. Three main emplacement geometries were identified: (a) at contacts between magmatic bodies and host rocks, (b) as lenticular or irregular bodies parallel to the host rock foliation, and (c) at the intersections of near-orthogonal faults. Although structural controls on skarn formation represent a key factor in ore emplacement, their analysis remains scarcely explored. This paper therefore contributes to filling this gap by providing a detailed characterization of the structural framework governing IOCG skarn development at Tatatila–Las Minas. The results improve understanding of IOCG systems formation and provide predictive criteria for mineral exploration in similar geological settings, potentially reducing exploration and mining risks.

The Las Minas area corresponds to an exhumed geothermal system considered a proxy for the deep part of the nearby Los Humeros active geothermal system. The stratigraphic succession is made up of: Palaeozoic-Miocene granitoids, a thick Jurassic- Cretaceous carbonate succession, Neogene lava flows and volcano-sedimentary deposits. Linked to a Miocene magma intrusion, marble and skarn rock-volumes developed by contact metamorphism and geothermal fluid flow. Faults are arranged in SW- and NNW-striking systems. These controlled the morphological evolution and favored Neogene-Quaternary dyke emplacement. Faulting gave rise to a tectonic depression where lacustrine sediments and pyroclastics deposited. Skarn rocks are mainly located at fault intersections and along pre-existing discontinuities, suggesting the role of bedding and/or fractures in channeling deep fluids. Results give inputs for exploration at depth of Los Humeros geothermal system.

This study examines the movement of students in suburban Detroit through open enrollment, or inter-district school choice. We examine whether absolute levels and changes in the district enrollment of Black, economically disadvantaged, and nonresident students are perceived as racial threats by suburban families, leading them to exit their local school districts, through school or residential mobility. Using a multilevel discrete time survival analysis, we found that, for each standard deviation increase in the absolute percentage of Black students in the district, resident students were nearly eight times more likely to use school choice to exit their district the subsequent school year, and for every standard deviation increase in the change of Black enrollment in the district, resident students were 32 times more likely to move to a new district. For every standard deviation increase in the absolute percentage of nonresident students in the district, a resident student was 3.5 times more likely to move to a different district. This study adds to the evidence that school choice policies may contribute to racial inequality and raises questions about the logic of shifting state education resources to nonresident districts, rather than investing in strengthening urban and exurban school systems.

The landscape surrounding the Kings Chamber, one of many corbelled dry-stone chambers sited along the river headwater streams of Putnam County in New York, has been paced on foot, measured by two-meter GPS, and surveyed to two-foot accuracy by solar-oriented transit. The skyline of the hill opposite this chamber contains large, well-separated stones. An hypothesis of human construction is offered, because 3 stones correlate well with a four-part solar year. If trees were absent, the sunset shadows made by these stones on the winter solstice, summer solstice and equinoxes would cross at a point inside an arc of large stones in front of the chamber. The chamber axis at azimuth 213 faces toward the most southerly possible moonset on the opposing horizon. The rising of this same moon can be viewed from the nearby smaller chamber, and some speculation is offered on lunar timing of burial ceremonies in Woodland times. Other stones on the horizon may correlate with the major lunar standstills, and with stellar directions nearer to the meridian, but do not suggest use of an 8-part year with solar cross-quarter days. Archaeological investigation with radiocarbon dating inside the chambers and around the stones is urged in order to help prove or disprove the hypothesis of human construction and date the chamber construction.

The energetics for water loss from Ba2+(H2O)x, where x = 1 – 8, and Sr2+(H2O)x, where x = 5 – 9, alkaline earth metal systems are investigated using a guided ion beam tandem mass spectrometer (GIBMS). Reaction cross sections are modeled with a modified empirical threshold model taking into account multiple effects to ensure accurate thermodynamic data. Dissociation enthalpies are then compared directly with values derived from quantum chemical calculations. These works complete the GIBMS investigation of the alkaline earth metals and comment upon periodic trends in bond dissociation enthalpy, coordination number, and the charge separation phenomena.Infrared multiple photon dissociation (IRMPD) investigations with a free electron laser (at FELIX) radiation source. The IRMPD work examined the Pt+ + x CH4/x CD4, where x = 1 – 4, and Ir+ + x CH4, where x = 1 – 4 systems. The experimental spectra of these reactions’ products are scaled and compared to spectra generated from quantum chemical calculations. Reaction coordinate pathways are reported that examine product formation pathways for aforementioned systems.

The TOPS intervention program at Porterville schools teaches at-risk students skills for getting along more peacefully with others. Walter Wheeler writes that the program is cost effective and results in more positive student behavior, creating a more pleasant campus atmosphere.